Axminster needle drive mechanism



Oct. 3, 1950 J. H. PFAU AxMINsTEE NEEDLE DRIVE MECHANISM Filed June 29,1949 Gttorneg JM /05 H PFA@ C7 Patented Oct. 3, 1950 AXMIN STER NEEDLEDRIVE MECHANISM Julius H. Pfau, Yonkers, N. Y., assignor to AlexanderSmith & Sons Carpet Company, Yonkers, N. Y., a corporation of New YorkApplication June 23, 1949, Serial No. 101,953

2 Claims. (Cl. 13S-123) mains constantregardless of changes in operatingspeed.

Various other objects and advantages will be apparent as the nature ofthe invention is more fully disclosed.

Axminster looms customarily include'a needle which is advanced entirelyacross the loom through the warp shed and cooperates at the end oi itsthrust with a shuttle which is adapted to interloop a selvage threadwith the double pick of weft inserted by the needle. Since the needlemust be at least as long as the width of the warp shed' and itsstroke isof a corresponding length, the needle-actuating mechanism possessesconsiderable inertia, particularly in wide looms. Due to this inertiaand the inherent iiexibility oi the actuating mechanism, it has beenfound that the iinal position ofthe needle at the end of its thrust mayvary by a substantial amount -when the loom is operating atvhigh speedsfrom its position at low speed, this variation at times being such as tointerfere with the proper functioning of the shuttle.

The present invention overcomes this difficulty by providing snubbermeans to oppose the advance of the needle, atleast during thedeceleration periods so that the effect of the iiexibility of the driveor lost motion in the driving mechansm is eliminated. The snubber meansacts to take up any lost motion in the connections and reverses theeliect of the exiblity of the drive so as to retard the needle thrustand bring the needle to rest at a predetermined point regardless ofchanges in operating speed.

The action of the snubber is further improved by introducing a flexibleelement at one or more points in the drive mechanism which is arrangedto allow the snubber to retard the needle with respect to the drivemechanism. This results in decreasing the rate of change of theneedlefeed during the periods of reversal which assists in overcoming theinertia eiects.

The details of the mechanism and the manner of its operation willbebetter understood by referring to the followingy description, taken inconnection with the accompanying drawing in which a specic embodimenthas been shownfor purposes of illustration.

In the drawing:

Fig. 1 is a somewhat diagrammatic side eleva- 2 tion of a drivemechanism embodying the invention;

Fig.A 2 is an enlarged detail View showing the construction of the driveand snubber; and

Fig. 3 is an enlarged section taken on the line 3 3 of Fig. 2 showingtheresilient connections in the drive mechanism. v

Referring to the drawing more in detail, the invention is shown asembodied in an Axminster loom having a needle II] mounted in a carriageI I which slides in a track on rails I2. It is to be understood that thelength of the needle IIJ and of the rails` I2 is such that the needle iscapable of reciprocating in a path extending through the warp shed ofthe loom.

The needle may be reciprocated by any suitable motion multiplyingmechanism. In the form shown this comprises two sets of movable sheavesI4 and I5 mounted on the upper end of an arm I6 which is pivoted at itslower end by a pin I1 to a link I8 and at an intermediate point by a pinI9 to a link 26. The links Ill and 20 are pivoted to iixed brackets 2iand 22, respectively. The link 20 Yis the same length as the portion ofthe arm I8" above the pin I9, and thus causes the upper end of the armIo and the sheaves I4 and I 5 to reciprocate in a straight line.

A cableZE is connected at one end to the carriage II and extends arounda xed pulley 26, thence back and forth several times between movablesheaves I4 Yand a set of stationary sheaves 2l and its other end is:anchored to a' frame 28 by means of a rod 29 and' is held under tensionby a spring 3B.

A cable 32 isconnected at one end to the carriage VII and extends arounda fixed pulley 33, thence back andrforth several times between movablesheaves i5 and a set of iixed sheaves 34 and its end is anchored to theframe 35 at 36. The arrangement is such that vreciprocation of the upperend of the arm IB causes the cables 25 and 32 to reciprocate thecarriage I I in its track along the rails I2, the sets of sheavesserving to multiinvention. Y

As illustrated in Fig. 3, the driving link 43 is formed in two parts 45and 46 which are connected by a flexible coupling. The part 45 is formedat its forward end with an annular flange 41 having a shoulder 48against which the outer metal ring 49 of a exible coupling is secured bya snap ring 50. The flexible coupling comprises outer and inner metalrings 49 and 5l bonded to an intermediate rubber ring 52 and is of thetype commonly used for vibration mountings. The rearward end of the part46 is held in the inner metal ring I which is seated against a shoulder53 and clamped by a nut 54.'

The rearward end of the part 45 is shown as forked and securedfto thepin 44 which is journalled inthe inner v'ring 58 of a vibration mountinghaving inner and outer metal rings 58 and 59 bonded to an intermediaterubber ring 60. The outer metal ring 59 is mounted in the crank arm 4l.

The forward end of the part 46 carries a similar vibration mountinghaving inner and outer metal rings 64 and 65 bonded to an intermediaterubber ring 66. The pin I9 is journalled in the inner metal ring B4 andextends through the double arm I6 and through the link 20.

It is understood that one or more of the vibration mountings may beomitted if sufficient flexibility is obtained by the inherent lostmotion of the couplings.

The snubber means is shown as comprising a fluid pressure cylinder 68pivoted at one end to a fixed bracket 'l0 and having a piston 12 on apiston rod 14 which extends from the free end of the cylinder 68 and ispivotally connected by a pin 16 to the arm I6 at a point above the pinI9, although the point of connection will depend upon the stroke of thecylinder 68. If a shorter cylinder is used, the point of connection willbe correspondingly lowered on the arm I6. In any event the snubber meansshould be located beyond the flexible couplings or beyond the principalsource of lost motion in the drive.

The cylinder is provided with an open valve'18 at its free end and witha vent 80 at its pivoted end connected to a flap valve 82 and anadjustable valve 84. The flap valve 82 opens inwardly to allow freereturn of the piston and the adjustable valve 84 provides for acontrolled cushioning or snubbing action on the advance of the piston,If desired the valve may be set to retain a part of the compression forrestoring the energy of compression during the return stroke of thepiston.

In the operation of this drive the crank arm 43 rotates at a constantrate and the arm I6 and needle carriage are reciprocated thereby. Duringthe portions of drive cycle where deceleration occurs the inertia of theneedle and of the drive mechanism tends to stretch the cables, flex thedriving arms, and the lost motion of the connections, which may be dueto the looseness of the couplings or to the resilience of the vibrationcouplings above described, is reversed from that occurring duringacceleration periods.

In the present construction the piston 12 serves as a snubber to take upthe lost motion during the deceleration of the needle thrust. This notonly eliminates the jerkiness due to reversal of the lost motion, buttends to retard the needle so that a positive driving force is requiredon deceleration as well as on acceleration.

The.. rate ofV change in feed at the instant of reversal is reducedbelow that corresponding to the normal drive motion and the needleposition at time of shuttle contact is made practically independent ofloom speed. Hence the loom may be operated at higher than normal speedswithout diiculty. The exibility of the drive is controlled to obtain apositive needle position at reversal.

The valves may be adjusted to produce the required cushioning effect andthe cylinders automatically produce greater cushioning pressure athigher speeds. Of course another cylinder may be used on the sidecorresponding to the retracted position of the needle or a single doubleacting cylinder may be used if desired.

It is to be understood that the invention is not restricted to theparticular type of drive shown, but may be used with other types ofmotion multiplying mechanism and is useful in general for reducing therate of change and reversal of reciprocating members. Variousadaptations will be apparent to a person skilled in the art.

What is claimed is:

1. In an Axminster loom having a needle adapted to be reciprocated tolay double weft shots through a warp shed, drive mechanism` connected toreciprocate said needle, said mechanism comprising a pivoted arm, motionmultiplying means connecting said arm to actuate said needle, acontinuously rotating drive member, connecting members connecting saiddrive member to cause reciprocating movement of said arm, and a fluidpressure cylinder having one end pivotally mounted and having a pistonrod extending through the free end thereof and connected to said pivotedarm, a piston attached to said rod, and vent means in said cylinderarranged to cause said piston to oppose the movement of said pivoted armduring periods of deceleration.

2. In an Axminster loom having a needle adapted to be reciprocated tolay double weft shots through a warp shed, drive mechanism connected toreciprocate said needle, said mechanism comprising a pivoted arm, motionmultiplying means connecting said arm to actuate said needle, acontinuously rotating drive member, connecting members connecting saiddrive member to cause reciprocating movement of said arm, and a fluidpressure cylinder having one end pivotally mounted and having a pistonrod extending through the free end thereof and connected to said pivotedarm, a piston attached to said rod, and vent means in said cylinderarranged l to cause said piston to oppose the movement of said pivotedarm during periods of deceleration, said vent means including anadjustable valve for controlling the effect of said cylinder.

JULIUS H. PFAU.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS 4 Number Name Date 1,366,514 Brais Jan. 25, 19211,492,723 Collins May 6, 1924 1,823,298 Stone Sept. 15, 1931 2,054,150Watson Sept. 15,1936 2,160,339 Moessinger May 30, 1939 2,258,191 PayneOct. 7, '1941

